Okay, I think this is a new one. Today on a long highway drive I noticed something strange with the oil pressure gauge (74 450slc). Usually pegged at 3 bars at highway speed, I was amazed to see it was reading between 2 and 3 bars, depending on throttle position. Goes down to 2 bars when floored, and back to 3 when the throttle is lifted completely. Temperature, oil level, are ok. Oil pressure reads about 1 bar at warm idle. Car is running very well otherwise, hope I'm not doing something destructive driving it with these readings.
Why would oil pressure ever drop while accelerating and rise again when coasting (vacuum related)? Anybody seen this one before?